The present invention relates to a filter drier and method of filtering a fluid stream and more particularly to an improved apparatus and method for filtering and drying liquid refrigerant in a refrigerant system. The present invention provides a unique and useful improvement to the method and apparatus disclosed in U.S. Pat. No. 4,637,881, issued to George J. Sciuto on Jan. 20, 1987.
As is discussed in above U.S. Pat. No. 4,637,881, filter driers utilizing a bed of desiccant beads .and filter pads for drying and removing particulate materials from fluid systems, such as refrigerant systems, are generally well known in the art and in refrigerant systems they have served to remove moistures and acids from the refrigerant, filtering particles of metal, dirt or grit from refrigerants to prevent operational damage to the compressors and other components of the system. It also has been generally well known in the art to provide filter media pads upstream and downstream beds of desiccant beads, attention being directed to U.S. Pat. Nos. 3,170,872, issued to S. Balough et al on Feb. 23, 1965; 3,815,752, issued to J. E. Hoffman et al on Jun. 11, 1974; 4,177,145, issued to E. W. Schumacher on Dec. 4, 1979; 4,209,401, issued to P. V. Henton on Jun. 24, 1980; 4,364,756, issued to J. P. Clarke et al on Dec. 21, 1982; and, to the aforementioned U.S. Pat. No. 4,637,881. This latter patent-recognizing past problems in the art relating to flow and filtration characteristics-- provides a unique apparatus and method which relies on both a fluid diffusion concept and a concept of desiccant compaction which is complimentary to fluid flow compaction to minimize desiccant roiling erosion and escapement, to enhance desiccant absorption and to generally enhance particulate filtering from the fluid stream treated. The present invention, recognizing the desirability of maintaining these unique concepts and at the same time recognizing certain limitations of the past art in filtering fine particulates from a fluid stream, such as might be present in a refrigerant stream prior to treatment or which might result as carryover from the filter treatment process itself, provides a still further unique apparatus and method which effectively prevents such fine particulate carryover from occurring in the treated fluid stream without substantially increasing pressure drop by utilizing generally known principals in a unique and novel manner.
Various other features of the present invention will become obvious to one skilled in the art upon reading the disclosure set forth herein.